NOMINAL PIPES SIZE & SCHEDULE

The size of pipes are defined by the combination of two dimensions:

  • Nominal pipe size: Nominal Pipe Size (NPS) is a North American set of standard sizes for pipes used for high or low pressures and temperatures. The European and international designation equivalent to NPS is DN (diamètre nominal/nominal diameter/Durchmesser nach Norm), in which sizes are measured in millimetres, see ISO 6708." (source: Wikipedia)
     
  • Pipe schedule: As the main function of the pipes is to carry fluid under pressure therefore their internal diameter is their critical dimension. This critical dimension is referred to as the nominal bore (NB). Obviously, for pipes containing pressurised fluids the wall thickness, and by implication the pipe’s strength, is important. Wall thickness is expressed in “schedules“, referred to as pipe schedules. The pipe schedule is abbreviated as SCH. For a given size and schedule the thickness of the pipe is fixed and defined in the applicable ASME standard. Other than the pipe schedule, pipe thickness can also be specified in mm or inches to the value corresponding to that specified in the ASME standard. (source: Piping-Engineering)

 

"Sch" meaning: The word "sch." stands for "schedule", i.e. the wall thickness of a pipe.

 

The standard pipe sizes are shown in the follwing tables:

NPS 1/8" – 3 1/2"

Standard Pipe sizes chart ASME B36 10 - first line: pipe wall thickness in inches; second line: pipe WT in mm (by nominal pipe size and pipe schedule)

NPS PIPE

DN

OD INCH (mm) WT (mm)
SCH 5s SCH 10s/ 20 SCH 30 SCH 40(s) / STD SCH 80(s) /XS SCH 120 SCH 160 XXS
1/8 6 0.404 (10.26) 0.035 (0.889) 0.049 (1.245) 0.057 (1.448) 0.068 (1.727) 0.095 (2.413)
1/4 8 0.540 (13.72) 0.049 (1.245) 0.065 (1.651) 0.073 (1.854) 0.088 (2.235) 0.119 (3.023)
3/8 10 0.675 (17.15) 0.049 (1.245) 0.065 (1.651) 0.073 (1.854) 0.091 (2.311) 0.126 (3.200)  
1/2 15 0.840 (21.34) 0.065 (1.651) 0.083 (2.108) 0.095 (2.413) 0.109 (2.769) 0.147 (3.734) 0.188 (4.775) 0.294 (7.468)
3/4 20 1.050 (26.67) 0.065 (1.651) 0.083 (2.108) 0.095 (2.413) 0.113 (2.870) 0.154 (3.912) 0.219 (5.563) 0.308 (7.823)
1 25 1.315 (33.40) 0.065 (1.651) 0.109 (2.769) 0.114 (2.896) 0.133 (3.378) 0.179 (4.547) 0.250 (6.350) 0.358 (9.093)
1 1/4 32 1.660 (42.16) 0.065 (1.651) 0.109 (2.769) 0.117 (2.972) 0.140 (3.556) 0.191 (4.851) 0.250 (6.350) 0.382 (9.703)
1 1/2 40 1.900 (48.26) 0.065 (1.651) 0.109 (2.769) 0.125 (3.175) 0.145 (3.683) 0.200 (5.080) 0.281 (7.137) 0.400 (10.160)
2 50 2.375 (60.33) 0.065 (1.651) 0.109 (2.769) 0.125 (3.175) 0.154 (3.912) 0.218 (5.537) 0.250 (6.350) 0.344 (8.738) 0.436 (11.074)
2 1/2 65 2.875 (73.03) 0.083 (2.108) 0.120 (3.048) 0.188 (4.775) 0.203 (5.156) 0.276 (7.010) 0.300 (7.620) 0.375 (9.525) 0.552 (14.021)
3 80 3.500 (88.90) 0.083 (2.108) 0.120 (3.048) 0.188 (4.775) 0.216 (5.486) 0.300 (7.620) 0.350 (8.890) 0.438 (11.125) 0.600 (15.240)
3 1/2 90 4.000 (101.60) 0.083 (2.108) 0.120 (3.048) 0.188 (4.775) 0.226 (5.740) 0.318 (8.077) 0.636 (16.154)


NPS 4" – 9"

Standard Pipe sizes chart ASME B36 10 - first line: pipe wall thickness in inches; second line: wt in mm (by nominal pipe size and pipe schedule)

NPS PIPE DN OD INCH (mm) WT (mm)
SCH 5 SCH 10(s) SCH 20 SCH 30 SCH 40(s) /STD SCH 60 SCH 80(s)
/XS
SCH 100 SCH 120 SCH 140 SCH 160 XXS
4 100 4.500 (114.30) 0.083 (2.108) 0.120 (3.048) 0.188 (4.775) 0.237 (6.020) 0.337 (8.560) 0.437 (11.100) 0.531 (13.487) 0.674 (17.120)
4 1/2 115 5.000 (127.00) 0.247 (6.274) 0.355 (9.017) 0.710 (18.034)
5 125 5.563 (141.30) 0.109 (2.769) 0.134 (3.404) 0.258 (6.553) 0.375 (9.525) 0.500 (12.700) 0.625 (15.875) 0.750 (19.050)
6 150 6.625 (168.28) 0.109 (2.769) 0.134 (3.404) 0.280 (7.112) 0.432 (10.973) 0.562 (14.275) 0.719 (18.263) 0.864 (21.946)
7 7.625 (193.68) 0.301 (7.645) 0.500 (12.700) 0.875 (22.225)
8 200 8.625 (219.08) 0.109 (2.769) 0.148 (3.759) 0.250 (6.350) 0.277 (7.036) 0.322 (8.179) 0.406 (10.312) 0.500 (12.700) 0.593 (15.062) 0.719 (18.263) 0.812 (20.625) 0.875 (22.225)  
9 9.625 (244.48) 0.342 (8.687) 0.500 (12.700)


 

NPS 10" – 24" (< SCH. 40)

Standard Pipe sizes chart ASME B36 10 - first line: pipe wall thickness in inches; second line: wt in mm (by nominal pipe size and pipe schedule)

NPS
PIPE

DN OD
INCH (mm)
WT (mm)
SCH 5s SCH 5 SCH 10s SCH 10 SCH 20 SCH 30 SCH STD/40S
10 250 10.75 (273.05) 0.134 (3.404) 0.134 (3.404) 0.165 (4.191) 0.165 (4.191) 0.250 (6.350) 0.307 (7.798) 0.365 (9.271)
12 300 12.75 (323.85) 0.156 (3.962) 0.156 (3.962) 0.180 (4.572) 0.180 (4.572) 0.250 (6.350) 0.330 (8.382) 0.375 (9.525)
14 350 14.00 (355.60) 0.156 (3.962) 0.156 (3.962) 0.188 (4.775) 0.250 (6.350) 0.312 (7.925) 0.375 (9.525) 0.375 (9.525)
16 400 16.00 (406.40) 0.165 (4.191) 0.165 (4.191) 0.188 (4.775) 0.250 (6.350) 0.312 (7.925) 0.375 (9.525) 0.375 (9.525)
18 450 18.00 (457.20) 0.165 (4.191) 0.165 (4.191) 0.188 (4.775) 0.250 (6.350) 0.312 (7.925) 0.437 (11.100) 0.375 (9.525)
20 500 20.00 (508.00) 0.188 (4.775) 0.188 (4.775) 0.218 (5.537) 0.250 (6.350) 0.375 (9.525) 0.500 (12.700) 0.375 (9.525)
22 550 22.00 (558.80) 0.188 (4.775) 0.188 (4.775) 0.218 (5.537) 0.250 (6.350) 0.375 (9.525) 0.500 (12.700) 0.375 (9.525)
24 600 24.00 (609.60) 0.218 (5.537) 0.218 (5.537) 0.250 (6.350) 0.250 (6.350) 0.375 (9.525) 0.562 (14.275) 0.375 (9.525)


 

NPS 14"- 24" (> SCH. 40)

Standard Pipe sizes chart ASME B36 10 - first line: pipe wall thickness in inches; second line: wt in mm (by nominal pipe size and pipe schedule)

NPS 
PIPE

DN WT (mm)
SCH 40 SCH 60 SCH 80s/XS SCH 80 SCH 100 SCH 120 SCH 140 SCH 160
    0.365 (9. 0.500 (12. 0.500 (12. 0.593 (15. 0.718 (18. 0.843 (21. 1.000 (25. 1.125 (28.
    0.406 (10. 0.562 (14. 0.500 (12. 0.687 (17. 0.843 (21. 1.000 (25. 1.125 (28. 1.312 (33.
14 350 0.437 (11.100) 0.593 (15.062) 0.500 (12.700) 0.750 (19.050) 0.937 (23.800) 1.093 (27.762) 1.250 (31.750) 1.406 (35.712)
16 400 0.500 (12.700) 0.656 (16.662) 0.500 (12.700) 0.843 (21.412) 1.031 (26.187) 1.218 (30.937) 1.437 (36.500) 1.593 (40.462)
18 450 0.562 (14.275) 0.750 (19.050) 0.500 (12.700) 0.937 (23.800) 1.156 (29.362) 1.375 (34.925) 1.562 (39.675) 1.781 (45.237)
20 500 0.593 (15.062) 0.812 (20.625) 0.500 (12.700) 1.031 (26.187) 1.280 (32.512) 1.500 (38.100) 1.750 (44.450) 1.968 (49.987)
22 550 0.875 (22.225) 0.500 (12.700) 1.125 (28.575) 1.375 (34.925) 1.625 (41.275) 1.875 (47.625) 2.125 (53.975)
24 600 0.687 (17.450) 0.968 (24.587) 0.500 (12.700) 1.218 (30.937) 1.531 (38.887) 1.812 (46.025) 2.062 (52.375) 2.343 (59.512)

 

SIZE CHARTS DOWNLOADS:

 Pipe schedule chart.pdf

 Pipe sizes calculation formula.pdf

 

PIPE DIAMETER CONVERSION CHARTS

(Nominal pipe size and outside diameter in inches and mm; conversion of nominal pipe size - NPS - to DN, i.e. "pipe nominal diameter")

PIPE NPS Pipe Outside diameter
in inches
PIpe Outside diameter 
in mm
NPS to DN
conversion
1/8 0.404 10.26 6
1/4 0.54 13.72 8
3/8 0.675 17.15 10
1/2 0.84 21.34 15
¾ 1.05 26.67 20
1 1.315 33.40 25
1 ¼ 1.66 42.16 32
1 ½ 1.9 48.26 40
2 2.375 60.33 50
2 ½ 2.875 73.03 65
3 3.5 88.90 80
3 ½ 4 101.60 90
4 4.5 114.30 100
4 ½ 5 127.00 115
5 5.563 141.30 125
6 6.625 168.28 150
7 7.625 193.68
8 8.625 219.08 200
10 10.75 273.05 250
12 12.75 323.85 300
14 14 355.60 350
16 16 406.40 400
18 18 457.20 450
20 20 508.00 500
22 22 558.80 550
24 24 609.60 600
26 26 660.40 650
28 28 711.20 700
30 30 762.00 750
32 32 812.80 800
34 34 863.60 850
36 36 914.40 900
38 38 965.20 950
40 40 1016.00 1000
42 42 1066.80 1050
44 44 1117.60 1100
46 46 1168.40 1150
48 48 1219.20 120

NPS RANGE COMMERCIAL PIPES

Material Group Execution NPS min NPS max
Carbon Seamless 1/8" 24"
  Welded 1/2" 80"
Stainless Seamless 1/4" 24"
  Welded 1/4" 36"
Alloy 20 Seamless 1/2" 8"
  Welded 6" 12"
Hastelloy C276 Seamless 1/2" 8"
  Welded 1/2" 12"
Duplex 2205 Seamless 1/2" 8"
  Welded 4" 24"
Duplex 2507 Seamless 1/2" 8"
  Welded 6" 12"
Monel 400 Seamless 1/2" 8"
  Welded 8" 12"
Inconel 600 Seamless 1/2" 8"
  Welded 8" 12"
Inconel 625 Seamless 1/2" 8"
Incoloy 800 Seamless 1/2" 8"
Incoloy 825 Seamless 1/2" 8"
  Welded 8" 12"
 

 

 

Looking for additional info? Contact the pipingonline expert team

Useful links: ANSI | ASME | ASTM | API | MSS | BS | DIN | ISO